Incorporating DFIG based wind power generation in microgrid frequency regulation

Although wind power as a renewable energy is assumed to be an advantageous source of energy, its intermittent nature causes some conflicts especially in islanding mode of operation. While, it is economical to compensate wind with a conventional synchronous generator, the slow behavior of such a system may result in some stability concerns. Here, virtual inertia method, which imitates the kinetic inertia of synchronous generator, is used to improve the dynamic behavior of the system. In order to prevent any additional cost of inverter or energy storage device, the proposed control is implemented in the grid side converter of the back-to-back inverter connected to the DFIG rotor. The rotor side converter of this inverter is used to extract the maximum available power of wind. The concept and the proposed control method are discussed in details. Several case studies are used to show that this control algorithm can improve the dynamic performance of systems in case of disturbances such as islanding. By letting dispatchable DGs choose lower droop coefficients, the steady-state behavior of the system can be improved indirectly, while the virtual inertia just provides the power for short term. This improvement is shown in the work while the proposed method is implemented.